<html>
<head><meta charset="utf-8"><title>PR #63909 fix nounwind logic · t-compiler · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/index.html">t-compiler</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/PR.20.2363909.20fix.20nounwind.20logic.html">PR #63909 fix nounwind logic</a></h3>

<hr>

<base href="https://rust-lang.zulipchat.com">

<head><link href="https://rust-lang.github.io/zulip_archive/style.css" rel="stylesheet"></head>

<a name="177049670"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/PR%20%2363909%20fix%20nounwind%20logic/near/177049670" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/PR.20.2363909.20fix.20nounwind.20logic.html#177049670">(Oct 01 2019 at 12:27)</a>:</h4>
<p><span class="user-mention" data-user-id="126931">@centril</span> I discovered today that <span class="user-mention" data-user-id="120791">@RalfJ</span> 's PR fixes <a href="https://github.com/rust-lang/rust/issues/64655" target="_blank" title="https://github.com/rust-lang/rust/issues/64655">#64655</a>. Would you be willing to remove your rfcbot concern based on that discovery?</p>



<a name="177049757"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/PR%20%2363909%20fix%20nounwind%20logic/near/177049757" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/PR.20.2363909.20fix.20nounwind.20logic.html#177049757">(Oct 01 2019 at 12:28)</a>:</h4>
<p>I'll look at this later and see</p>



<a name="177049758"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/PR%20%2363909%20fix%20nounwind%20logic/near/177049758" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/PR.20.2363909.20fix.20nounwind.20logic.html#177049758">(Oct 01 2019 at 12:28)</a>:</h4>
<p>(I'm happy to add a commit to the PR that encodes a regression test adapted from <a href="https://github.com/rust-lang/rust/issues/64655" target="_blank" title="https://github.com/rust-lang/rust/issues/64655">#64655</a> ...)</p>



<a name="177049764"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/PR%20%2363909%20fix%20nounwind%20logic/near/177049764" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/PR.20.2363909.20fix.20nounwind.20logic.html#177049764">(Oct 01 2019 at 12:28)</a>:</h4>
<p>okay thanks</p>



<a name="177149733"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/PR%20%2363909%20fix%20nounwind%20logic/near/177149733" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/PR.20.2363909.20fix.20nounwind.20logic.html#177149733">(Oct 02 2019 at 13:31)</a>:</h4>
<p>hey <span class="user-mention" data-user-id="124289">@rkruppe</span> or <span class="user-mention" data-user-id="123586">@nagisa</span> , would one of you be able/willing to assist me in dissect why LLVM is behaving this way for this case? I have been unsuccessful thus far in reproducing the situation in a <code>#![no_core]</code> style test</p>



<a name="177149839"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/PR%20%2363909%20fix%20nounwind%20logic/near/177149839" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/PR.20.2363909.20fix.20nounwind.20logic.html#177149839">(Oct 02 2019 at 13:32)</a>:</h4>
<p>(that is, I have been trying to simplify things by moving the relevant functionality into its own crate distinct from <code>core</code>. but when I do so, then the bug with unwind and uncalled-drop disappears)</p>



<a name="177152793"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/PR%20%2363909%20fix%20nounwind%20logic/near/177152793" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Hanna Kruppe <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/PR.20.2363909.20fix.20nounwind.20logic.html#177152793">(Oct 02 2019 at 14:04)</a>:</h4>
<p>Can you at least reduce it to just a no_std crate + core?</p>



<a name="177152838"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/PR%20%2363909%20fix%20nounwind%20logic/near/177152838" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/PR.20.2363909.20fix.20nounwind.20logic.html#177152838">(Oct 02 2019 at 14:05)</a>:</h4>
<p>Yeah I actually got it down to something I was able to dissect</p>



<a name="177152849"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/PR%20%2363909%20fix%20nounwind%20logic/near/177152849" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/PR.20.2363909.20fix.20nounwind.20logic.html#177152849">(Oct 02 2019 at 14:05)</a>:</h4>
<p>I'll be posting in the bug soon, but I don't think I need help anymore</p>



<a name="177152856"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/PR%20%2363909%20fix%20nounwind%20logic/near/177152856" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Hanna Kruppe <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/PR.20.2363909.20fix.20nounwind.20logic.html#177152856">(Oct 02 2019 at 14:05)</a>:</h4>
<p>Ok, glad to hear that</p>



<a name="177152890"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/PR%20%2363909%20fix%20nounwind%20logic/near/177152890" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/PR.20.2363909.20fix.20nounwind.20logic.html#177152890">(Oct 02 2019 at 14:05)</a>:</h4>
<p>If you are curious, this gist holds my reduced case: <a href="https://gist.github.com/425ddc19aa968bbc36b8cb46fab7d15d" target="_blank" title="https://gist.github.com/425ddc19aa968bbc36b8cb46fab7d15d">https://gist.github.com/425ddc19aa968bbc36b8cb46fab7d15d</a></p>



<a name="177152946"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/PR%20%2363909%20fix%20nounwind%20logic/near/177152946" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/PR.20.2363909.20fix.20nounwind.20logic.html#177152946">(Oct 02 2019 at 14:06)</a>:</h4>
<p>(compiling that with <code>-C opt-level=0 -C lto=fat</code> shows the problem.)</p>



<a name="177152958"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/PR%20%2363909%20fix%20nounwind%20logic/near/177152958" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Hanna Kruppe <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/PR.20.2363909.20fix.20nounwind.20logic.html#177152958">(Oct 02 2019 at 14:06)</a>:</h4>
<p><em>nod nod</em> that looks great</p>



<a name="177186723"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/PR%20%2363909%20fix%20nounwind%20logic/near/177186723" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/PR.20.2363909.20fix.20nounwind.20logic.html#177186723">(Oct 02 2019 at 20:02)</a>:</h4>
<p>okay I filed PR <a href="https://github.com/rust-lang/rust/issues/65020" target="_blank" title="https://github.com/rust-lang/rust/issues/65020">#65020</a> as a more targeted fix that I think everyone can get on board for (orthogonal to the Q of whether PR <a href="https://github.com/rust-lang/rust/issues/63909" target="_blank" title="https://github.com/rust-lang/rust/issues/63909">#63909</a> lands) and will be amenable for beta-backport.</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
</html>